An arabinogalactan from fruits of Lycium barbarum L. inhibits production and aggregation of Aβ42

The β amyloid (Aβ) induced neurodegeneration is believed to be one of pathological mechanisms of Alzheimer's disease (AD). The inhibition of Aβ production or aggregation is one of the promising therapeutic strategies for anti-AD drug discovery. Here, a homogeneous neutral polysaccharide designated LBP1A1-1 with an average molecular weight of 45.0 kDa was purified from fruits of Lycium barbarum L. Its structure was characterized to possess a backbone of 1, 3-linked β-Galp, 1, 6-linked β-Galp, 1, 4-linked α-Glcp with branches substituted at C-3 position of 1, 6-linked β-Galp or C-6 position of 1, 3-linked β-Galp. The branches contained terminal (T)-linked β-Galp, T-linked α-Araf, T-linked β-Araf, 1, 5-linked α-Araf and T-linked β-Rhap. The in vitro experiments revealed that LBP1A1-1 could inhibit Aβ42 production and impede Aβ42 aggregation in a dose-dependent-manner without cytotoxicity. These results suggested that LBP1A1-1 might have the multiple potential for the treatment of AD.